When a train operation diagram becomes irregular due to accident or disaster, some train services may be suspended, necessitating changes in car operation scheduling. Changing this scheduling is a large and complicated task involving many trains and train sets, and requires consideration of a number of constraints such as the type of train set and the location of trains. As the revised plan is usually created manually in an emergency, the scheduling quality may be unsatisfactory, including unnecessary runs of deadheading trains late at night. In this study, a new algorithm was developed to create efficient car operation schedules minimizing train cancellation and deadheading trains, while at the same time satisfying existing constraints and taking into account each train's operational requirements.
      If, for example, a train set cannot exit a depot due to a point failure at the depot entrance, an operation schedule may be created by simply cancelling the relevant train in the depot along with its turn-back train. However, this method may cause passenger inconvenience due to successive train cancellations (Fig. 1). This algorithm, on the other hand, can create a schedule without successive train cancellations (Fig. 2). The operation scheduling is substantially changed at terminal stations by considering the compatibility of the train type and set type as well as the train location matching. The algorithm works quickly (within a matter of seconds in the case of Fig. 2) enough to enable immediate creation of operation schedules in response to situation changes such as alteration in the recovery time schedule.